Transparent glass-ceramic laserable articles containing neodymium

ABSTRACT

Glass ceramics capable of luminescence or induced emission. An activator, e.g. neodymium, is used to impart said properties. The glasses can be used in lasers and masers.

United States Patent Neuroth Dec. 23, 1975 TRANSPARENT GLASS-CERAMIC [56] References Cited LASERABLE ARTICLES CONTAINING UNITED TA ENT NEODYMIUM 3,504,819 4/1970 Veres l06/39.6 [75] Inventor; Norbert New-0th, MainLMombach, 3,535,266 10/1970 Lee, Jr. 252/301.4 F Germany 3,597,179 8/1971 Simmons 106/39.8 3,617,317 11/1971 Sack et a1. 106/39.8 [73] Assignee: Janaer Glaswerk Schott & Gen., 3,642,504 2/1972 Petzold et a1. 106/39.8 Mainz, Germany 3,725,811 4/1973 Murphy 252/301.4 F 3,788,865 1/1974 Babcock et a1. 106/39.7 [22] Filed: May 8, 1973 [21 A 35 224 Primary ExaminerPatrick P. Garvin Assistant ExaminerMark Bell Related Apphcatmn Data Attorney, Agent, or Firm-Burgess, Dinklage & [63] Continuation of Ser. No. 86,010, Nov. 2, 1970, Sprung abandoned.

[30] Foreign Application Priority Data Nov. 3, 1969 Germany 1955174 [57] ABSTRACT .Glass ceramics capable of luminescence or induced 52 us. Cl. 252 301.6 P; 252/3014 P; emission An activator, neodymium, is used o im- 252/3() 4 252/301 25 /30 5 part said properties. The glasses can be used 'in lasers 252/3014 R; 156/47 Q; 156/396; and

156/39.7; 156/52 [51] Int. Cl. C09K 11/08; CO3C 3/22;

3 3 (309K 11/10 10 Claims, 3 Drawing Figures [58] Field of Search 106/52, 39.6, 39.7, 39.8,

106/47 Q; 252/3014 F, 301.4 R, 301.4 D, 301.6 P, 301.6 F, 301.6 R

US. Patent Dec.23, 1975 Sheet1of2 3,928,229

/-VNr0 BY NORBERT NEUROTH ATTORNEYS E t 5g 2% W n/r04 BY NORBERT NEUROTH 2 B bimkaaa'ad s AT TORNE Y5 TRANSPARENT GLASS-CERAMIC LASERABLE ARTICLES CONTAINING NEODYMIUM This is a continuation of application Ser. No. 86,010 filed Nov. 2, 1970, now abandoned.

A large number of crystalline materials and glasses are known which luminesce and can be excited to induced emission due to the incorporation of one or more types of activation ions. The crystals have certain physical properties which are determined by the type of crystal involved. In the case of glasses, the characteristics can be constantly varied by the systematic variation of their chemical composition, so as to approximate desired values.

A new group of solid materials is represented by substances referred to as glass ceramics. The production of a glass ceramic commences with production of glasses of certain compositions, which in a second step of the process are transformed to glassy-crystalline bodies by heat treatment. This heterogeneous structure results in special characteristics. For example, glass ceramics can be made whose thermal expansion is virtually zero. Such materials are extremelyresistant to thermal shock. 7

It has now been found that glass ceramics are also suitable as host materials for activation ions. The activating ions can be used in small amounts effective to impart the stated properties, e.g. 0.1-10, or 1-8, preferably 1-5 wt. calculated as an oxide. If, for example, ions of the rare earth group are incorporated into them, they can be excited to luminescence. For example, it has been found that neodymium ions can be incorporated into a transparent glass ceramic of extremely low thermal expansion and excited to luminescence. Production of the glass ceramics suitable as hosts for the activators is described in U.S. Pat. application Ser. No. 716,316, filed Mar. 27, 1968, now abandoned; Ser. No. 740,317, filed June 26, 1968, now U.S. Pat. No. 3,617,317; Ser. No. 743,580, filed July 1, 1968, now U.S. Pat. No. 3,642,504.

Ions of the following elements are suitable as activators. Chromium, manganese, nickel, copper, cerium, praseodymium, neodymium, samarium,europiu'm, gadolinium, terbium, dysprosium, holmiur'n, erbium, thulium, ytterbium or uranium ions, a mixture hereof.

In FIG. 1 there is shown the spectral curve of the luminescence emission J. The stronger emission is at 1,060 nm, and two weaker emission bands occur at 900 nm and 1,330 nm.

In FIG. 2 there are shown the absorption spectre of two glass ceramics containing neodymium. Curve a is the curve for a glass ceramic containing 2% neodymium oxide, and curve b represents a glass ceramic containing 5% neodymium oxide.

FIG. 3 shows a device for generation of ultra high frequency energy emission, in the form of a laser or maser outfitted with an activated glass ceramic 2, as a molecular oscillator.

Table 1 and Table 2 set forth compositions and the most important properties of luminescent glass ceramics according to the invention. Ranges are given in Table 1 specific compositions in Table 2. The luminescence decay time in the first three glass ceramics of Table 2 is greater than 200 microseconds, a value which is desired in laser design. The thermal expansion is lower than that of quartz glass, and is very important in withstanding the great thermal shocks which the laser rod undergoes when excited by the powerful flash lamps.

The production of these luminescent glass ceramics is performed by the processes described in the abovecited patent applications, the activator ions being incorporated into the glass batch in the form of the oxides as the other constituents of the glass are incorporated.

I Table 1 I Broad Range Preferred Range wt.7r wt.%

SiO 5O 70 60 70 P 0 10 0 6 A1 0; 16 2O Li O 2 8 2 4 Na O 0.2 2 0.2 2 Mg0 0 3 0.5 3 CaO 0 3 0 1 ZnO 0.5 3 0.5 3 TiO 1.0-3 1.0-3 ZrO, 1.0-3 1.0-'3 AS203 0 2 O 2 Sb203 0 2 O 2 Nd o 1 8 2 5 MgO CaO 0.5 3 0.5 2

Intensity of luminescence of the 1060 nm bands (relative values) 3 3 35 Luminescence decay time (microseconds) 25 or 25 400 200 or 200 350 Thermal expansion 0.2 5 i 0.2 5 (20 to 30C). 10/C v Sp. Gravity 2.25 2.75 2.45 2.6

Table '2 Compositions in wt.% and characteritistics of neodymium-activated glass ceramic Si0 67 0 65.0 64.0 54.2 P 0 5.0 7.7 A1 0 18.5 17.9 19.0 24.7 Li 0 2.8 2.7 3.2 3.7 Na 0 0.7 0.7 0.5 0.5 MgO 1.0 1.0 0.7 1.0 CaO 0.8 0.7 ZnO 2.9 2.9 0.7 1.4 "IiO 1.5 1.4 2.6 2.2 ZrO 1.8 1.7 1.8 1.9 A5 0 0.5 0.7 Sb O 1.0 1.0 Nd 0 2.0 5.0 2.0 2.0

Intensity of Luminescence of the 1060 nm bands (relative values) 30 24 4 4 Luminescence decay time (microseconds) 330 220 240 Thermal expansion 2.4 4.0 0.5

(20 to 30) 10/C Spec. Gravity 2.51 2.56 2.51 2.54

In the Table 1 compositions, neodymium can be replaced by the same molar amount of any of the ions mentioned above as being suitable as activators; mixtures of the activators can be used.

EXAMPLE 63.1 kg silicon dioxide 23.6 kg aluminum hydroxide 7.9 kg lithium carbonate 0.7 kg zinc oxide 1.5 kg magnesium carbonate -contlnued X (1 kg aluminum orthophosphnte 0.5 kg arsenic oxide l.4 kg sodium nitrate 2.6 kg titanium oxide 2.7 kg zirconium silicate 2.0 kg neodymium oxide The mixture of raw materials is melted in a fireclay furnace at 1600C in 12 hours and refined for 20 hours at l.620C. The melt is poured into the desired molds and annealed from 680C down. In order to transform the glass without deformation to a transparent glasscrystal mixture, the glass is heated at a rate of 2C per minute to 700C, held at this temperature for 30 minutes, then heated, again at a rate of 2C per minute, to 810C and kept at this temperature for 90 minutes. After the ceramization, the object is cooled to room temperature.

What is claimed is:

l. A laserable article consisting of transparent glass ceramic as host material containing activating ions rendering the article capable of induced emission, the activating ions being neodymium ions in amount of 0.1-10 wt.-% calculated on the oxide.

2. Article according to claim 1, containing 1-8 wt% neodymium calculated on the oxide.

3. Article according to claim 1, containing 1-5 wt% neodymium calculated on the oxide.

4. A laserable article consisting essentially of transparent Li O-Al O -SiO glass ceramic as host material containing neodymium ions rendering the article capable of induced emission, the amount of neodymium being 0. l-l wt.% calculated on the oxide.

5. A laserable article consisting essentially of transparent glass ceramic as host material containing neodymium ions rendering the article capable of induced emission, the composition of the glass in weight being:

SK) 50 70 p 0,, 0 l0 Al O l5 30 U 0 2 8 Na:() .02 2 Mg() 0 3 CaO 0 3 7.110 0.5 3 TiO 1.0 3

6. Article according to claim 5, having:

Intensity of luminescence of the 1060 nm hands (relative values) 3 35 Luminescence decay time (microseconds) 25 Thermal expansion 0.2 5 20 to 30C. X l0 /C Sp. Gravity 2.25 2.75

7. Article according to claim 5, the thermal expansion at 20-30C, X l() /C, being 0.2 5.

8. Article according to claim 5, consisting essentially of the following composition in wt.%

nocc'o's'ut lll 9. Article according to claim 8, having:

Intensity of luminescence of the I060 nm hands (relative values) 3 35 Luminescence decay time microseconds) 200 Thermal expansion 0.2 5 20 to 30C. l0 lC Sp. Gravity 2.45 2.6

10. Article according to claim 8, the thermal expansion coefficient at 20-30C, l0 /C, being 0.2 5.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,928,229

. DATED December 23, 1975 |NVENTOR(S) Neuroth Norbert It is certified that error appears in the above-Identified patent and that said Letters Patent are hereby corrected as shown below: q Column 2, line 18, (Table 1), change "T10 to --TiO Column 3, line 43, change ".02-2" to --0,2-2-., Column 4, line 13, change "25" to 25--. Column 4, line 39, change "200" to 200" o Signed and Scaled this Eighth 13a) of March 1977 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ofPatenls and Trademarks 

1. A LASERABLE ARTICLE CONSISTING OF TRANSPARENT GLASS CERAMIC AS HOST MATERIAL CONTAINING ACTIVATING IONS RENDERING THE ARTICLE CAPABLE OF INDUCED EMISSION, THE ACTIVATING IONS BEING NEODYMIUM IONS IN AMOUNT OF 0.1-10 WT. 5 CALCULATED ON THE OXIDE.
 2. Article according to claim 1, containing 1-8 wt% neodymium calculated on the oxide.
 3. Article according to claim 1, containing 1-5 wt% neodymium calculated on the oxide.
 4. A laserable article consisting essentially of transparent Li2O-Al2O3-SiO2 glass ceramic as host material containing neodymium ions rendering the article capable of induced emission, the amount of neodymium being 0.1-10 wt.% calculated on the oxide.
 5. A laserable article consisting essentially of transparent glass ceramic as host material containing neodymium ions rendering the article capable of induced emission, the composition of the glass in weight % being:
 6. Article according to claim 5, having:
 7. Article according to claim 5, the thermal expansion at 20*-30*C, X 107/*C, being 0.2 -
 5. 8. Article according to claim 5, consisting essentially of the following composition in wt.%
 9. Article according to claim 8, having:
 10. Article according to claim 8, the thermal expansion coefficient at 20-30*C, X 107/*C, being 0.2 -
 5. 